Date: Sat, 15 Aug 1998 04:26:36 -0500 From: VaX#n8 <vax@linkdead.paranoia.com> To: netbsd-users@netbsd.org, freebsd-hackers@FreeBSD.ORG, tech@openbsd.org, linux-kernel@vger.rutgers.edu Subject: ups/power management techniques Message-ID: <199808150926.EAA00661@linkdead.paranoia.com>
next in thread | raw e-mail | index | archive | help
Apologies for sending to such a broad audience. I have been working quite hard on a cable, adapting electronics, and UPS monitoring software for NetBSD. I sent an email to the vendor about building a cable, and was told it wasn't possible. Naturally, I could not resist this challenge. I examined the Linux UPS HOWTO, various web pages, and built my own (learning quite a bit about RS-232 in the process). I was a little surprised to find that most of the serial communication information on the Internet began and ended with pin assignments. I couldn't even find a suitable newsgroup to ask questions in. After investigating several of the Linux packages, I decided it would still be worthwhile (instructive) to write my own. I've done so. However, my UPS only supports immediate shutdown (by raising a serial line for 50 milliseconds). This led to some rather interesting race conditions when trying to implement it in a stand-alone daemon. So, I figured I'd query the collective open-source knowledge base. Searching various mailing list archives has tended to generate more heat than light - there's a number of terms and synonyms people could use in describing the issue, and there are far more people asking where to find a particular software package than in discussing the real issues. So the questions I want to ask are: 1) What kind of kernel support would handle this in the cleanest way? 2) Where should the shutdown signal be asserted; in the userland monitoring program, the reboot command, the kernel reboot(2), or the instruction before HALT? ;) 3) Should there be any special handling after a powerfail shutdown? Specifically, should the OS idle in single-user mode until some condition is met, to avoid yo-yo-ing? 4) Anything else? I will summarize in a web page, so you need only email me and check my home page later (see the mail headers). Cc any mailing list at your own peril. While I wouldn't mind a cross-list technical discussion about the various approaches, they haven't worked in the past. Apologies for my semi-literacy; it has been a long night. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199808150926.EAA00661>